Feed locking mechanism for sewing machines



R. KAIER Feb. 11, 1941.

FEED LOGKIG NECHANISMV FOR'SEWING HAGHINES Filed June 30', 1939 2 Sheets-Stragi'. A1

l n r 1 kf. N

Richard Kaden Deceased Eleanor Ci Iaenllcecu 1 Feb. 11, 1941. l R, KMER 2,231,164

FEED LOCKING IECHANISM FOR SEWING MACHINES Filed June so, 1959 2 sheets-sheet z Richard Kaviar; Deoease l'leanor C. Koller; Evecurx immane Patented Feb. 11, 1,941

UNITED STATES PATENT OFFICE y FEED LOCKING MECHANISM FOR SEWING MACHINES Richard Kaier, deceased, late of Cranford, N. J., by Eleanor C. Kaier, executrix, Cranford, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application June 30, 1939, Serial No. 282,162

11 claims.

producing stitches of greater length than desired by the manufacturer. In cases where the manufactured articles must conform to definite specifications as to stitch-length, this unauthorized l lengthening of the feed-stroke is serious inasmuch as it sometimes results in the rejection of an entire lot of the manufactured articles.

This invention therefore has as an object to provide a simple mechanism which will effectively prevent the operator or other unauthorized persons from increasing the length of the feedstroke.

A further object is to provide a feed-locking device of this nature which lreadily may be applied to sewing machines now in use, without the necessity of performing any machining operations thereon. y

With the above and other objects in view, as

will hereinafter appear, the invention comprises the devices, combinations and arrangements of l parts Ahereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advanas rtages, attained thereby will be readily understood by those skilled in the art.

Fig. 1 is a side view of a sewing machine einbodying the present invention.

Fig. 2 is a vertical sectional view taken substantially on the4 line 2-2 of Fig. 1.

Fig. 31s an enlargedlongitudinal sectional view of the improved locking device, removed from the machine, together with its actuating key.

Fig. 4 is a/perspeotive view of the improved locking device.

Fig. 5 isa perspective view of the key which cooperates with the lock shown in Fig. 4.

Fig. 6 is a view showing a plurality of stopscrews adapted selectively to be used in the improved lock for varying the position of the feedcontrol lever, as hereinafter will be described.

Referring more specifically to the drawings, the invention is disclosed as embodied in a Singer Class 95 sewing machine comprising a cloth-plate sa I, standard 2, ovcrhanging arm 3 and. a needlebar carrying head 4. A reciprocatory needle-bar 5, mounted in the head 4, carries a needle 6 which cooperates with a rotary loop-taker 1 to form stitches. The loop-taker is secured upon a shaft 8 journaled in bearings formed in bearing lugs 9 5 and i0 depending from the cloth-plate I. The needle-bar is actuated from a main-shaft Il, journaled lengthwise in the arm 3, by a crankand-link mechanism designated generally as 1:. The loop-taker shaft 8 is rotated from the main- 10 shaft by means of a pair of bevel gears I2, I3, connecting the main-shaft with an upright shaft I4 journaled in the standard 2, and a second pair of bevel gears I5, I6, connecting the shaft Il with the loop-taker shaft. 18 'I'he machine also includes a work-feeding mechanism comprising a feed-bar I1, carrying a feed-dog I8, adapted to be given upward and downward and backward and forward movements thereby to give to the work the usual feed- 20 ing movement after each retraction of the needle from the work. As is well understood, the length of the stitch formed is'dependent upon the length of the feeding movement of the feed-dog.

The means for giving to the feed-bar, and the 25 feed-dog carried thereby, their vertical and horizontal movements and the means for controlling the amplitude of the horizontal movement are similar to those disclosed in United States Patent te Miner and Diehl, No. 229,629, July 6, 1880.

Rising and falling movements are given to the feed-bar l1 by an eccentric I9 on the main-shaft II acting through a pitman 20 connected, at 2I, to an arm 22 which projects laterally from the rear end of a rockshaft 23 journaled lengthwise 35- of the machine beneath the cloth-plate I. At its forward end, the rock-shaft 23 carries a second arm 24 which is connected with the forward end of the feed-bar.

-The means for giving to the feed-bar its end- 40 wise reciprocating motions comprises an eccentric 25 secured upon the main-shaft II, a block 28 surrounding the eccentric and a connecting rod 21 having its upper forked end 21* engaging the y, sides of the block 26 and its lower end pivotally 45 connected, at 28,`to an arm 29 secured upon a feed-drive rock-shaft 30. At its forward end the rock-shaft 30 carries another arm 3| which is connected to the feed-bar I1 as shown in Fig. 2. Y Adjacent its upper end the connecting rod 21 has 50 pivotally connected to it, at 21", one end of an anchor-link 32 the other end of which is pivoted. at 32e, to one arm of a normally stationary feedregulating bell-crank lever 33 fulcrumed on a shoulder-screw 33a threaded into the arm 3. One 55 arm 33c of the lever 33 carries an element which projects through a slot 3 in the machine-frame for the purpose of adjustment. Horizontal movements of the block 26, under the iniiuence of the eccentric 25, causes the connecting rod 21 to be oscillated about its pivot 28. Due to the connection of the anchor-link 32 to the connecting rod 21 and to the normally fixed pivot 32'. this oscillatory motion of the connecting rod causes the pivot pointV 21b to be moved in the arcuate path indicated by the -dot-dash line y-y in Fig. 2. movement of the connecting rod therebyeffecting, through the arm 29, oscillatory motion of the feed-drive rock-shaft 30, thus giving to the feed-bar its endwise reciprocations or work-feeding and return movements.

The amount of endwise movement given to the connecting rod 21, and consequently the amount of horizontal reciprocation given to the feed-bar I1, is dependent upon the angular position of the anchor-link 32. This position may be changed by shifting the feed-regulating lev'er 33 about its fulcrum 33a. The more nearly vertical is the link 32 the less will be the endwise movement of the connecting rod 21 and the shorter will be the feed-stroke. Heretofore the lever 33 has been held in its various positions of adjustment by a clamp-screw which was under the control of the operator, as shown in the above mentioned Miller and Diehl patent. Therefore, to increase the length of feed, operators have frequently released the clamp-screw and adjusted the feed-regulating lever 33 downwardly, in violation of orders to the contrary,

The present invention provides locking means to prevent the operator from shifting the forward arm of the feed-regulating lever 33 downwardly to increase the stitch-length, whereby the stitchlength may `be increased only by some person of authority having the necessary control key. This means comprises a-clamp-screw 34, threaded into the arm 33c of the feed-regulating lever, having a truncated conical head 35 provided with a concentric bore 36 and an eccentric aperture 31. The tapered head 35 is relatively smooth and is hardened to prevent rotation of the clamp-screw by means of pliers, wrenches or other readily available tools. Mounted upon the clamp-screw 34 is a sheet-metal stop-bracket 38 comprising a disk-like head 38a having therein an aperture 38h to receive the shank of the screw 34, a horizontally arranged portion 38, threaded to receive one of a plurality of adjustable stop-screws, later to be referred to, and an upstanding leg 38d having in its upper surface a notch 38e the arcuate wall of which is adapted to contact with the shank of the clamp-screw 34. At its upper edge the disk-like portion 38a is formed with an integral tab 38i designed to be bent downwardly over the conical head 35 of the screw 3.4, as shown most clearly in Fig. 3, thereby to prevent disassembling of the clamp-screw and the bracket 38. A threaded aperture 38*g in the portion 38C of the stop-bracket 38 is adapted to receive any one of a plurality of stop-screws designated as a, b, and c, in Fig. 6. The lower end of the stopscrew is adapted to engage the lower wall 3b of the slot 3a through which the clamp-screw 34 extends. Thus the wall 3b, through the stopscrew and the leg '38d of the stop-bracket 38, limits the downward movement of the screw 34 and the feed-regulating lever arm 33C. Inasmuch as each of the stop-'screws is adjustable lengthwise in the stop-bracket 38 each screw This movement in turn causes endwiseaffords a limited adjustment of the feed-regulating lever thereby providing a variation in the feed of approximately five stitches per inch. Major adjustments are effected by substituting a screw of different length.

After one of the screws a, b or c have been threaded into the bracket 38 andadjusted so that when its head rests on the Wall 3b the desired length of feed is secured, the screw 34 is turned to tightly clamp the parts in that position, the portion 38 of the stop-bracket binding against the outer arcuate surface of the frame at opposite sides of the slot 3. This adjustment and clamping is effected by a foreman, or other auth'orized person, by means of a removable key (Fig. comprising a hub 40 having a circular extension adapted to fit Within the bore 36 in the head of the clamp-screw 34, a projecting eccentric pin 42 designedto fit within the eccentric aperture 31, and a transverse rod 43 adapted to serve as a means for manually rotating the key.

It will readily be perceived that after the feedregulating lever has been adjusted and locked by some authorized person and the key removed, it is impossible for the operator to adjust the feed to lengthen the stitch.

Inasmuch as the above described locking device is a self-contained unitary structure it' will be perceived that it may be readily substituted for the conventional' feed clamp-screw of machines now in use by merelyjunscrewing the clamp-screw (such as f2 in the Miller and Diehl patent) from the feed-regulating lever and replacing it with the unit illustrated in Fig. 4.

Having thus set forth the nature of the invention what is claimed herein is:

1. A sewing machine combining a frame having a slot therein, work-feeding mechanism, a. regulator for said feeding mechanism including an adjusting lever aligned with said slot, means to lock said lever in its various positions of adjustment comprising a clamp-screw extending through the slot in said frame and-threaded into said adjusting lever, and means carried by said clamp-screw and engaging an end wall of said slot to prevent movement of said screw toward said end wall.

2. A sewing machine combining a frame having a slot therein, work-feeding mechanism, a regulator for said feeding-mechanism including an adjusting lever aligned with said slot, means to lock said lever in its various positions of adjustment comprising a clamp-screw extending through the slot in said frame and threaded into said adjusting lever, and adjustable stop means carried by the shank of said lclamp-screw and adapted to engage an end wall of said slot to limit the movement of said clamp-screw toward said end wall.

3. A sewing machine combining a frame having a slot therein, work-feeding mechanism, a regulator for said feeding mechanism including an adjusting lever aligned with said slot, means to lock said lever in its Various positions of adjustment comprising a clamp-screw extending through the slot in said frame and threaded into said adjusting lever, a stop-bracket carried by the shank of said screw, and a stop-screw Acarried by said bracket and adapted to engage an end'wall of said slot to prevent movement of said screw toward said end wall.

, 4. A sewing machine combining a frame having a slot therein, work-feeding` mechanism, a regulator for said feeding mechanism including an adjusting lever alignedfwithsaid s1ot,`means yto lock said lever in its variouspositions of adjustment; cemprsing a clamp-screw', extending y .through the SloiinSaid-frme 'andthreaded into said adjusting lever; ajsheet'-metaly stop'bracketf carried byusaid clamp-screw and comprising" up- .standing end portions engagingl the' shank of said screw and a .mid-portionconnecting said lengthen the'feedi e end portions provided with'afthread'ed apertura' and a stop-screw threadedinto Asaid 'aperture and' `adapted fto engage oneencl wall of said .slot to prevent movement of vsaidzlever in a direction vto A unitarylocking device forthe-feed-regulati'ng lever-of a sewing'jmachine having a slot in theframe thereof in "alignrnentr with a portion of said lever, comprising agkclamp-screwadapted toe'xtend through said slot and to be threaded into said lever;`saidciarpp-screw having a head formed to receives, locking ke'ya stop-member carried by saidclamp-screw and adapted to enhead.

gage entend wall` of said/slot thereby to limit the feed-adjusting movement` ofsaid feed-regulating lever and a removable locking key fitted to said Y 6. A unitarylockingdevice for thefeed-regulatinglever of asewing ymachine having a slot in Vtl'xe'frarrie thereof inalignment with aportion of said lever comprisinga clamp-screw adapted to extend throughsaid slotv and to be threaded into said lever,A said clamp-screw having va head 'of 1 `truncated conical formeprovlded withv a central bore and an eccentricaperture, a stop-member .carried `byl .said clamp-screw and adapted to eni gage' one end wall of said slot thereby to limit` the feed-adjusting movement offs/aid feed-regulating lever, and a keyfhavin'g portions complemental to said bore and aperturdadapted to roformed to receive a. locking keyfa stop-bracket y carried by the shank of saidY clamp-screw, a

stop-screw threaded intosaid stop-bracket and y adapted to engage one end wall of the slot in said frame to prevent movement of said feedregulating lever in a direction to lengthen the feed. and a key `:fitted to the head of said clampscrew to rotate the latter to effect clampingand it 55 unclamping of said lever.

8. In a sewingmachine vided with a slot, work-feeding mechanism and a regulator for said feeding mechanism including an .adjusting lever aligned with saidslot, the comment comprising a clamp-screw 'extending' through the slot in said frame and threadedinto having a frame probination with said adjusting lever of means to lock said lever in its various positions of adjust-1 -v e *n i Eecutrirc of the Last said adjusting-lever,,said clamp-screw having a V4head of'truncated conical form adapted, upon rotation of 'saidscrewin one direction'to friction- ;ally, engage said frame ,therebyl impositively to resist shift-ing'of said adjusting lever,` means interposed loetit'een said `clamp-screw and an end wallof said slot'` positively to prevent movement o'jfsaid screw toward said wall, and aremovable key adapted to engage the head of said clampscrew to rotate the latter.4

9. In a `sewing machine, a'locking means for the feed-adjusting lever thereof as set forth in .claim-8. in which'th head of the c1ampscrew is formed with a concentric bore and an eccentrlc'aperture, andl in which the key has portions adapted to t within said bore land aperture to prevent relative .rotation between the key and the clamp-screw. i s

10.I A,y sewing machine combining a frame having a slot therein, Work-feeding mechanism, a regulator for said feeding mechanism including 'an adjusting lever'l aligned with said slot, means to lock said lever in its various positions .of adjustment comprising a 'clamp-screw extending through the slot in said frame and threaded into said adjusting lever, a sheet-metal stopb'racket carried by said clamp-screw and comprising offset end portions engaging the shank of said screw. and a mid-portion, connecting said endportions, provided with a threaded aperture adapted to receive therein any one 'of a plurality `of stop-screws of unequal lengths, the inserted'stop-screwbeing adapted to engage one end wall of said slot thereby to position the clamp-screw and feed-adjusting lever to produce different predetermined lengths of feed and to prevent movement of said llever in a direction to lengthen the predetermined lfeed-stroke.

l1. A- feed-regulating llever vlocking device adapted to be applied, as Va una-to a sewing machine having a frame formed with a slot thereframe, adjacent said slot, the friction produced by said pressure tending to resist reverse manual l.rotation of said clamp-.screw thereby to prevent ready removal of the clamp-screw, stop means carried by the shank of said clamp-screw and engagingV one end wall of said slot to prevent movement'of said screwto'ward said end wall, and-a removable key iitted to the head of said .v clamp-screw and adapted to facilitate manual `rotation thereof.

ELEANOR C. KAIEB. Will and Testament of Richard Kater, Deceased. 

